The specific aims of the present research application are directed at identifying and characterizing taste cell- expressed proteins that enhance taste receptor function. In vivo, these proteins may play a role in optimizing taste cell function, or they could play a role in adaptation to external taste stimuli by regulating the number of functional receptors at the taste cell surface. Taste tissue will be analyzed by PCR techniques to screen for the presence of members of the RTF and Reep families, which may function to enhance taste receptor activity. Each RTF and Reep protein found in taste will be tested for its enhancing properties on tastant receptors using expressed taste receptors in heterologous cells. Any potential interactions of RTFs or Reeps with taste receptors will be confirmed by immunoprecipitation and confocal microscopy. Finally, the mechanism of action of these enhancing proteins will be investigated using structural and functional studies. [unreadable] [unreadable] [unreadable]